To determine the torque of an internal combustion engine, it is generally known to measure the torsion of one driving shaft. In so doing, one determines a resulting torque where the torque produced by the engine is decreased by the amounts which, for example, are used for ancillary components.
European Patent No. EP 0190206 describes a device for measuring and regulating the operating data of internal combustion engines. It describes producing a test signal, e.g., to regulate the exhaust-gas recirculation, by utilizing the ionization of the combustion gasses at high temperatures, by measuring the electrical conductivity of the partially ionized combustion gasses, using a voltage.
The disadvantage of the related art with respect to measuring the torsion of the driving shaft is that vibrations occur which lead to inaccuracies in the evaluation.
An object of the present invention is to determine the average engine torque (gas torque) (combustion torque) more efficiently and accurately.
The procedure according to the present invention has the advantage that the torque (combustion torque) produced during combustion is determined directly from the signal from the ion current sensor and, thus, from an internal engine quantity.
The term combustion torque denotes the entire torque produced by the combustion in the cylinder. It breaks up into wheel torque, which is ultimately available to the drive, and torques, which are to be provided due to friction losses and for the ancillary components.
While the wheel torque plays a major role in vehicle performance, knowing the combustion torque is important for protecting the engine in order to prevent a thermal overloading due to too high a power output.
An additional advantage is that the torque contribution, which must be provided for the ancillary components, is also considered, thereby making it possible to determine the actual normal output produced by the engine. By fitting all cylinders with an ion current sensor, the average combustion torque, as well as the cylinder-related, individual torques can be determined. These torques can be used as input variables for a method for coordinating the cylinders.